1. Field
The following description relates to a faulty cell detection device and a faulty cell detection method to detect a faulty cell of a battery pack using a current sensor.
2. Description of Related Art
Generally, secondary batteries are batteries that can be charged and discharged unlike primary batteries for which charging is impossible. The secondary battery is used as an energy source of compact mobile devices, such as cellular phones, notebook computers, camcorders, wearable devices, or medium and large capacity devices such as electric vehicles, hybrid electric vehicles, electric bicycles, an energy storage system (ESS), an uninterruptible power supply (USP), robots, satellites, etc.
A compact mobile device, among the above-described devices, uses a few battery cells for one device. On the other hand, because the medium and large capacity devices, such as electric vehicles, hybrid electric vehicles, electric bicycles, an ESS, a UPS, robots, or satellites need high output power and high capacity, the medium and large capacity devices use battery packs in which a plurality of battery cells are electrically connected to each other.
Generally, the battery cells included in the battery pack include fuses which block radio waves generated by an explosion occurring in a breakdown to protect the battery cells from damage due to the explosion. When a breakdown of battery cells occurs and a fuse is cut off due to such breakdown during the operation of the battery pack, in the normal cells of the battery pack including a faulty cell that is blocked by the fuse, an overcurrent flows compared to the current before the occurrence of the breakdown of the battery cells. The overcurrent is generated because a current flowing through the faulty cell instead flows through the normal battery cells. Further, as a result of a current of an amount more than initially designed flows through a normal battery of the battery pack including the faulty cell, the cells degrade with a reduced life.
As described above, when one battery cell in the battery pack has a breakdown, there is a problem in that lifetime reduction of other battery cells included in the same battery pack is expedited due to a chain reaction from the breakdown. Therefore, studies are continually being conducted to accurately determine a state of a battery and detect a breakdown of the battery.